It's not easy being the newbie on The Real Housewives of Orange County -- just ask Heather Dubrow.

Dubrow's costar Gretchen Rossi recently visited Us Weekly's New York City offices, where she admitted to being quick to judge the wealthy brunette.

"I feel so bad because the new Housewife Heather Dubrow is actually the sweetest girl ever, and I really got to know her and like her a lot," Rossi said. "However, when I first met her, she seemed a little pretentious to me. I think the exact words out of my mouth were, 'I think you have a stick up your ass.' It didn't go over quite well when I first started with her."

Rossi even mocked Dubrow's acting career in a confessional, saying "I've never heard of you before." In hindsight, the 33-year-old said she didn't mean to offend Dubrow. "To my defense, unless you are truly an A-list actor, people aren't going to know your name."

Dubrow, 43, "added a fun dynamic to the group this season," Rossi told Us. "She's very straightforward. She just tells you how it is and she doesn't hold back."

For more details on how Dubrow is shaking things up on the reality series -- including how she frequently "butts heads" with Alexis Bellino -- watch the video (above). The Real Housewives of Orange County airs Tuesday at 9 p.m. EST on Bravo.